The development of high sensitivity pulsed light, time-resolved fluoroimmunoassays

Abstract

In this presentation, we review the basic concepts underlying immunoassay techniques, emphasising the distinction between “competitive” methods (which may rely on labelled antigen or labelled antibody) and “non-competitive” methods, which generally rely on labelled antibody. These two forms of assay are characterised by different sensitivity constraints, implying that, in practice, the non-competitive methods may display sensitivities several orders of magnitude greater than competitive techniques.To exploit the sensitivity potential of the non-competitive methods, very high specific activity labels characterised by high signal/noise ratios are required. Pulsedlight time resolving fluorescence measurement techniques, using lanthanide-chelate labels, offer such characteristics. We give a brief description of this methodology which has already been exploited in a number of working immunoassays. © 1985 IUPAC